You are more prone to sides by taking a bolus rather than disbursing the amounts BID/TID throughout the day....
With that being said, if you are a Powerlifter, you will most likely benefit more from taking all 50mg 30mins before your training so that you get a large burst of CNS activation amongst other benefits I don't feel like writing out.
Also, it has pretty much been anecdotally proven(at this point, I would almost just say scientifically...) that distributing doses of a short half-life drug causes better anabolic muscle gains than taking it all at once. I know some people will argue about this.... but yeah that's up for debate. If you were taking something like tbol which has a ~16 hour half life, I could understand just taking it once, but even in that case I would think AM/PM would be better, but probably not by far. However, something like dbol with a 3-4 hour half life....well, IMO you should just go ahead and distribute it to at least 2x a day; and perhaps a 3rd before you train.
If you want better muscle gains, and less sides, go ahead and just take the dbol 20 AM, 20 PM, and perhaps 10 PREWORKOUT or just put the 10 in a different dose. It's really not that big of an inconvenience(or at least shouldn't be imo) if you have made the decision that you want to use anabolic steroids...
I would think you wouldn't care about such a small thing, assuming you have to go to GREAT leaps and bounds(or should be...) to make sure you're having great nutrition which takes quite a bit of time....and to train hard ....and to monitor your health...and to take supplements to watch your health...
=o
PS: I would think the heartburn alone from taking 50mg at once would be enough to convince you to spread it out(assuming you got real dosed potent dbol and you experience this side like most users)... hah...